Cannot believe I'm the first to write a review. Purchased this manual not long after it was printed in '85. Long but excellent. Coverage of cold environment survival is superb. Haven't read more of the Air Force manuals but have lived in cold climates and whereof it speaks. Army manual FM 21-76 is also good, especially for warm and hot climates as is "Bushcraft" by Richard Graves of Australia. 64-4 is 569 pages so it takes more than an afternoon's perusing.